Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

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The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

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Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON3):

Solution:
def isNullified():
    for i in range(n):
        if max(matrix[i]) != 0:
            return False
    return True


def processRows():
    for i in range(n):
        minValue = min(matrix[i])
        if minValue != 0:
            content = "row " + str(i + 1)
            result.extend(minValue * [content])
            for j in range(m):
                matrix[i][j] -= minValue


def processCols():
    for i in range(m):
        column = [row[i] for row in matrix]
        minValue = min(column)
        if minValue != 0:
            content = "col " + str(i + 1)
            result.extend(minValue * [content])
            for j in range(n):
                matrix[j][i] -= minValue


if __name__ == "__main__":

    inpt = input().split()
    n = int(inpt[0])
    m = int(inpt[1])

    matrix = []
    result = []

    for i in range(n):
        row = list(map(int, input().split()))
        matrix.append(row)

    if n < m:
        processRows()
        processCols()
    else:
        processCols()
        processRows()

    if isNullified():
        print(len(result))
        print('\n'.join(result))
    else:
        print(-1)